Double-eccentric center butterfly valve also known as high-performance butterfly valve, mainly suitable for water plants, power plants, steel mills smelting, chemical engineering, water source engineering, environmental facilities construction and other system drainage, especially for the waterway pipeline, as a regulation and interception equipment. Compared with the Central Line butterfly valve, double eccentric butterfly valve is more resistant to high pressure, longer life, good stability. Compared with other valves, the larger the caliber, the lighter the material, the lower the cost. However, due to the butterfly plate in the middle, the flow resistance is large, so less than DN200 butterfly valve is not very significant.